The subject invention is directed to the preparation of alkaline earth metal sulfonate emulsions in general, and to the amine-free preparation of the same in particular.
The reduction or elimination of solvent emissions for environmental reasons has generated great interest in the handling of sulfonates in a water medium. Of particular interest are structurally modified overbased calcium sulfonates (SACI(copyright), Stoney Creek Technologies, LLC, hereinafter xe2x80x9cStoney Creekxe2x80x9d) which are frequently used as rust preventatives. More specifically, such sulfonates serve as, inter alia, coatings for the protection of metal surfaces, and as bases for the formulation of temporary coatings for the protection of painted automotive surfaces during transportation (transit coatings for automobiles). Such uses, however, first require emulsified sulfonate products with application-specific properties.
For instance, the transit coating market requires a coating which is low in volatile organic compounds (xe2x80x9cVOC""sxe2x80x9d), water borne or solvent free, capable of drying quickly, water resistant when dry, easily removed when desired, and one which provides protection of the painted surface from the effects of acid rain, air borne contaminants, bird droppings and any other potential source of paint damage. Finally, when removed, the transit coating must not show any evidence of having changed the appearance of the painted surface. The preparation of emulsified sulfonate products meeting these criteria proved to be a challenge.
During the development of such commercial emulsion products, it was found that at least some existing modified overbased alkaline earth metal sulfonates were not readily emulsifiable by traditional methods of choice, namely addition of an amine/fatty acid at high temperature. A series of experiments suggested the need for significantly high quantities of diluent oil as well as the addition of an oxidized low molecular weight polyethylene in order to facilitate emulsification. The use of a volatile amine/fatty acid was found to be necessary to ensure development of a dry film that is highly resistant to re-emulsification after application to the substrate.
The resulting commercialized product in its most basic form (SACI(copyright) 450W, Stoney Creek) and the method of manufacturing same both were attendant with serious disadvantages. These included the heretofore mentioned need for large amounts of diluent oil which resulted in a very fluid and oily film, and perhaps of even greater significance, the need for the use of a volatile organic compound, namely morpholine, as an emulsifier.
Morpholine has been implicated in causing various environmental and health-related problems. Classified as a VOC by environmental regulators, morpholine is prohibited in certain market areas, including Canada and Scandinavian countries. The use of compounds with levels of VOC above certain legislated limits (varying by geographical location) is now illegal. Moreover, emulsified sulfonates containing morpholine have compatibility problems with painted automotive finishes and with certain asphalt emulsions. Based on the serious shortcomings and limitations associated with the use of morpholine as an emulsifier, viable alternatives were vigorously investigated.
A first proposed solution to the above problems was to formulate a morpholine-free sulfonate emulsion by replacing morpholine with a fatty amide. The resulting commercial product proved difficult to manufacture and still required the addition of an amine such as dimethyl amino ethanol (DMAE) for stabilization of viscosity. This free amine also presented a problem from a VOC point of view and, therefore, was not a desirable alternative. Moreover, while this product did meet nearly all of the criteria set forth above for transit coatings, it failed to meet one: no change in appearance. All of the amide products developed did occasionally cause a slight whitening or haze to appear on some types of automotive paints during laboratory test procedures. Extensive laboratory testing led to the conclusion that the inclusion of the amine DMAE or the presence of amine derivative compounds was most likely responsible for the hazing or whitening phenomenon. This problem served as additional incentive to develop an amine free emulsion of anti-corrosive sulfonate based products.
The subject invention has successfully obviated most of the shortcomings and limitations of amine-based sulfonate emulsions. The novel emulsification system described herein provides for the formulation of emulsions of various sulfonates, including structurally modified overbased alkaline earth metal sulfonates (SACI(copyright) sulfonates), alone, or in combination with selected additives without the use of amines. Of considerable interest and importance is the fact that said amine-free emulsified sulfonates may be manufactured with only the addition of water and relatively small amounts of a single ingredient to the modified sulfonate base.
Applicant has discovered that a solution of water and a nonionic, associative thickener (e.g. Acrysol SCT 275, Rohm and Haas) of the type normally used for viscosity and thixotropy modification of latex compounds (typically latex paints) can be used for the amine-free emulsification of sulfonates. Of special interest are calcium sulfonates of the overbased type and specifically, structurally modified, overbased calcium sulfonates (e.g. SACI(copyright) 200 and 200A, Stoney Creek). Also of interest and great practical benefit is the ability to produce mixtures of these emulsified products with other ingredients such as neutral diluent oils, linear alcohol/hydrocarbon mixtures (i.e., Epal 20+, Ethyl Corp.), tall oil fatty acids, non-ionic surfactants, oxidized polyethylene waxes, small levels of microcrystalline wax, petrolatums, and/or calcium salts of oxidized petrolatums (i.e., Alox 606, Alox Corporation).
The resulting emulsions may be used for the modification of asphalt emulsions or as bases for the formulation of temporary coatings for the protection of painted automotive surfaces (transit coatings for automobiles). Typically, this involves the addition of a latex, often an SBR type. These compounds may also be employed for the prevention of corrosion of metal surfaces.
Indications are that other types of sulfonates (metal salts such as Magnesium and Barium) may also be emulsified by the same techniques, though the stability and utility of the resulting emulsions has not been fully explored.
Of particular interest is the fact that the process can be accomplished at atmospheric pressure and at temperatures near ambient, typically 150xc2x0 F. or less. Elevated temperature is primarily used to improve handleability of the highly viscous SACI(copyright) or 200A starting materials and the various mixtures thereof.
There has thus been outlined, rather broadly, the more important features of the invention in order that the detailed description thereof that follows may be better understood, and in order that the present contribution to the art may be better appreciated. There are, of course, additional features of the invention that will be described hereinafter and which will form the subject matter of the claims appended hereto. In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting. As such, those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention.
Further, the purpose of the foregoing abstract is to enable the U.S. Patent and Trademark Office and the public generally, and especially the scientists, engineers and practitioners in the art who are not familiar with patent or legal terms or phraseology, to determine quickly from a cursory inspection the nature and essence of the technical disclosure of the application. The abstract is neither intended to define the invention of the application, which is measured by the claims, nor is it intended to be limiting as to the scope of the invention in any way.
It is, therefore, a primary object of the subject invention to provide amine-free emulsions of various sulfonates, including structurally modified overbased alkaline earth metal sufonates, either alone or in combination with selected additives.
It is another primary object of the subject invention to provide amine-free emulsions of structurally modified overbased alkaline earth metal sulfonates which may effectively be employed as, inter alia, protective metal surface coatings and as bases for automotive transit coatings.
Another object of the subject invention is to provide a method for the production of amine-free emulsions of structurally modified overbased alkaline earth metal sulfonates at atmospheric pressure and near-ambient temperature.
It is also an object of the present invention to provide a method for the production of amine-free emulsions of structurally modified overbased alkaline earth metal sulfonates mixed with other ingredients such as neutral diluent oils, linear alcohol/hydrocarbon mixtures, tall oil fatty acids, oxidized polyethylene waxes, microcrystalline waxes, petrolatums, and/or Calcium salts of oxidized petrolatums.
It is another object of the present invention to create emulsions of non-modified sulfonates which can be used in metal working applications.
Still another object of the present invention is to provide a means of improving compatibility between sulfonate corrosion inhibitors and water borne resins.
Yet another object of the present invention is to create emulsions which provide improved pigment wetting and dispersion in water borne resin systems.
Another object of the present invention is to provide amine free emulsions of non-modified sulfonates for use as corrosion inhibitors in heat transfer media and equipment such as radiators and cooling towers.
These together with other objects of the invention, along with the various features of novelty which characterize the invention, are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its advantages and the specific objects attained by its uses, reference should be had to the accompanying detailed description of the preferred embodiments of the invention.